Amazon.com begins selling a jumbo-screen Kindle electronic reader this summer. But the book is still open on whether the students and newspaper readers that Amazon is targeting will embrace the Kindle DX's $489 jumbo price tag or whether the device will help fortifying the ailing media business.

Amazon.com Inc. is widely expected to unveil a new Kindle electronic book device with a larger screen Wednesday, which would be geared for textbooks, magazines and newspapers and possibly shake up the economics of multiple industries at once.